> On Feb 15, 2025, at 11:24 PM, Steve Lewis via cctalk <cctalk@classiccmp.org>
> wrote:
>
> I'm not very familiar with ALGOL, but just today I met someone at VCF who
> has essentially built a replica of the LGP-30 (in FPGA form, more on that
> to come down the road, but it is a system from 1955/1956). Then related to
> that, two different people mentioned to me of an early ALGOL compiler being
> available for the LGP-30. I don't know if that was of a form to be
> considered any kind of "block structure" as you mentioned.
It would be great to learn more about that. It's a rather early machine for
ALGOL to show up there, though a precedessor of ALGOL (IAL, "International
Algebraic Language") appeared in 1958. That was a bit of a mess and the 1960
Report on ALGOL-60 is quite different. Apparently IAL served as the
inspiration for JOVIAL, though in my view the designer of JOVIAL clearly
demonstrated that he didn't at all understand the core principles of IAL or
ALGOL.
A lot of early "ALGOL" compilers did major subsetting because it was considered
to hard to do the real language. Those subsets may not actually bear any real
resemblance to the actual language. For example, a "subset" that omits
recursion is not ALGOL but rather a mongrel joke.
One of the major contributions of Dijkstra and Zonneveld isn't just that they
built the first compiler for the full ALGOL-60, but that they invented all the
major compiler construction mechanisms to make that possible. This is analyzed
very well and in impressive detail in the Ph.D. Thesis of Gauthier van den Hove.
paul
